20865

Appears in sequences

• a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (composite numbers), t = (odd natural numbers).at n=39A025104
• a(n) = (2*n+1)*(10*n+1).at n=32A033574
• Numbers n such that Maple 9.5, Maple 10, Maple 11 and Maple 12 give the wrong answers for the number of partitions of n.at n=17A110375
• Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 1100-0111-0001-0001 pattern in any orientation.at n=10A147288
• Number of 6-element subsets of {1, 2, ..., n} having pairwise coprime elements.at n=24A186982
• a(n) = n*(14*n - 11).at n=39A195021
• a(n) = (n-2)*(14*n-39) for n > 2, otherwise a(n) = n.at n=41A195030
• Partial sums of A253089.at n=31A255601
• Relative of Hofstadter Q-sequence: a(n) = max(0, n+20830) for n <= 0; a(n) = a(n-a(n-1)) + a(n-a(n-2)) + a(n-a(n-3)) for n > 0.at n=32A283887
• Number of compositions (ordered partitions) of n into parts with an even number of distinct prime divisors.at n=36A286225
• Setwise difference A340150 \ A340076.at n=43A340151